Voice recognition technology has been recognized as an advantageous feature for many product applications. Such technology may be employed to render a product partially or entirely controllable by voice commands in situations where hands-on control is impossible or impracticable. Presently, however, voice recognition technology has not found wide use due to the complexity of its implementation, and requirements for a large amount of electronic storage (memory).
Speaker dependent voice recognition devices are designed to respond to a particular individual. Stored within such devices are speaker specific parameters, such as, for example, variations in the vocal tract response, pitch period, short-term speech power, and amplitude of the short-term speech spectra. In order for a speaker dependent device to respond to more than one person, the voice recognition information (commonly referred to as a "codebook") for each person must be stored within the device. However, mass codebook storage in each subscriber unit (radio) may prove impractical due to space or cost considerations. An alternative may be to use speaker independent technology, however, speaker independent devices are typically more complex and costly.
When applied to information communication devices, voice recognition technology raises several concerns. One major concern comprises the recognition that communication devices are typically used by more than one individual. For example, police vehicles are generally in service for three eight-hour shifts, during which at least three officers use the vehicle. Moreover, the officers using the vehicle (radio) may be anyone on the entire police force. Therefore, each radio must contain a codebook for each officer on the force. This would significantly increase the cost of the radios. Additionally, codebook maintenance costs would be significant since the radios must be updated with each change in personnel. Another concern is the increase in radio size. Contemporary state-of-the-art communication devices are designed so as to minimize their physical size. The addition of several memory devices, or a memory printed circuit board, may increase the size of the device beyond that desired by the consuming public. This is a particular concern in the personal pager and handheld radio products.
One solution may be to store the codebooks of only a few individuals thereby reducing the amount of required memory. However, this approach is inflexible to changing circumstances such as variations in personnel working hours or in the event that the radio itself should fail. Another approach may be to have each radio contain only enough memory for a single codebook, which must be retrained for each person. Speaker dependent voice recognition devices must be "trained" to respond to each individual. Training is accomplished by having an individual repeat control words several times until the device has been "trained" to recognize that word as spoken by that individual. However, training is a time consuming process and may be very inefficient in certain markets, such as police and fire protection, where rapid activity is ordinarily required Accordingly, a need exists in the art to permit information communication devices to be programmed to respond to the voice commands of several individuals in an efficient and organized manner.